1. Field of the Invention
This invention relates to a surgical stapling apparatus, and more particularly to an apparatus for clamping vascular tissue and subsequently driving an individual staple through the tissue and into contact with a staple forming anvil.
2. Description of the Related Art
Surgical apparatus for applying clips to vascular tissue are well known in the art. In these devices, each leg of the clip, typically U-shaped in configuration, is held in one of the opposing jaws of the instrument and the jaws are placed on sides of the vessel. The jaws are then closed to flatten the clip to squeeze the vessel walls together to effect hemostasis. These prior apparatus suffer from the disadvantage that the clip can only be advanced into the jaws of the instrument when the jaws are open so that vessel clamping and clip closing occur simultaneously. As a result, the surgeon cannot first ensure the vessel is properly clamped before committing to clip closure. Another disadvantage of these clip appliers is they can only be utilized to close a single vessel since they straddle the vessel; they cannot be used to attach approximated vessels or vessel portions.
Another prior method for repairing vascular tissue is suturing. Although two approximated vessels can be attached by this method, it is not only time consuming, but is difficult to accomplish in certain procedures, especially when the vessel is not in an easily accessible location or when microvascular tissue is involved. Still another disadvantage of suturing is that numerous punctures are made in the vessel walls since a hole is created with each passage of the suture needle.
Instruments for applying single staples one at a time to body tissue are also known. These instruments differ from the clip appliers in that they provide one jaw which contains a staple and an opposing jaw which contains an anvil for deforming the legs of the staple. For example, U.S. Pat. No. 3,278,107 discloses a device where closing of the handles clamps the vessels and forms a single staple. This instrument suffers from the disadvantage associated with the above described clip appliers since clamping of the tissue and application of the staple occur simultaneously. U.S. Pat. No. 3,604,561 also discloses a stapler having a pair of clamping jaws and a mechanism for advancing the staple into an anvil. When sufficient force is applied to the handles, the staple is driven through the tissue and into the anvil. This instrument is deficient in that premature firing could occur if too much force is applied to the handles during the initial clamping action.
The need therefore exists for an improved surgical stapler which can apply staples one at a time to body tissue such as vascular tissue and in which premature firing of the staples, e.g. firing before the tissue is satisfactorily clamped, is prevented. Such an instrument could be utilized for closing individual vessels as well as attaching approximated vessels.
The present invention overcomes the deficiencies and disadvantages of the prior art by providing a surgical stapling apparatus comprising a first handle member with an elongated jaw at its distal end having a plurality of staples positioned thereon and a second handle member comprising a second elongated jaw at its distal end having an anvil positioned thereon. The two handles are pivoted in scissor-like fashion to move the jaws to a closed position to clamp body tissue therebetween. Trigger means, independent of the pivoting means for closing the handles, actuates the staple pusher means to advance a single staple through the tissue and into contact with an anvil. The trigger means may be slidably mounted proximally of the pusher means for movement between a rest position and a biased position to pivot the pusher means. In one embodiment the trigger means is connected directly to the pusher means. In an alternate embodiment, an actuating lever can connect the trigger means to the pusher means. The actuating lever may include a cam slot which receives a pin extending from the trigger means so that proximal movement of the trigger means causes the pin to pivot the actuating lever as it travels in the cam slot. The actuating lever preferably includes an inwardly extending member which is received in a channel of the pusher means to pivot the pusher means into engagement with the staple.
An interlocking mechanism may be provided to prevent pivotal movement of the actuating lever unless the instrument jaws are closed. The interlocking mechanism may be in the form of a slidably mounted locking pin engaging a cut-out portion of the actuating lever.
The staple advancing means may be movable in the direction which is at an angle to the longitudinal axis of the anvil jaw. A removable staple cartridge can be provided containing a plurality of staples which are also angled with respect to the longitudinal axes and are fed one at a time into the firing path of the staple advancing means.